Approach

[1] In a small microwave-safe bowl, combine the sliced shallot, vinegar, sugar, 2 tablespoons of water, and salt. Cover the bowl with plastic wrap and microwave on high, 2 minutes. Drain well and let the shallots cool. The pickled shallot can be made ahead and refrigerated up to 1 day.

[2] On each potato chip, layer 1 piece of smoked salmon, a dollop of sour cream, 2 rings of pickled shallot, and a tarragon leaf.